FOR NVIDIA USERS:
I've removed the
nvidia-bl-dkms package from the PPA because it does not work anymore with Ubuntu 12.04 kernels.
If backlight control does not work for you, follow these instructions:
- Edit the file '/etc/X11/xorg.conf' and add this line into the Device section:
Code:
Option "RegistryDwords" "EnableBrightnessControl=1"
- Reboot and check if backlight control works. If so, you're done.
- If not, edit the file '/etc/default/grub' and change the line:
Code:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
toCode:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
- Update grub with this command:
Code:
sudo update-grub
- Reboot and backlight control should work.
NOTES:
The new
samsung-tools 2.0 has support for 2 different control interfaces:
samsung-laptop and
easy-slow-down-manager.
The first one is newer and is officially shipped with the newer linux kernels. Eventually, It will superseed easy-slow-down-manager.
Unfortunately, at the moment it lacks support for a lot of Samsung notebook models and it yet suffers of some annoying bugs.
The
samsung-laptop package available on the PPA installs a patched version of the kernel module which fixes some of these bugs but, yet, the situation is pretty much the same. If you face problems with this control interface, you can switch to the old 'easy-slow-down-manager' interface.
To do so, install the
easy-slow-down-manager and
samsung-backlight packages from the PPA. The 'samsung-laptop' kernel module will be disabled.
These 2 packages provide the same functionalities as in the previous Ubuntu versions, so if they worked for you, they will continue to do so.
You can check the control interface currently in use from the command line, with the command "samsung-tools -i", or through the "Samsung Tools Preferences" configuration dialog.
Another thing needs to be pointed out.
I receive a lot of reports about samsung-tools and the problems with the screen brightness control.
Samsung Tools has no control on screen brightness levels, nor on the behaviour of the Fn-Up and Fn-Down hotkeys used to control brightness.
It just controls the screen backlight (on or off, Fn-F5 hotkey), by using the control interfaces described above.
If brightness control does not work for you, then the problem may be in the kernel driver missing support for your notebook model, may be a bug in gnome-power-manager (if you use Gnome), may be a bug in powerdevil (if you use KDE), and so on.
Please file bug reports appropriately.

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